Compositions and methods using microspheres and non-ionic contrast agents

ABSTRACT

The present invention relates to compositions and methods for treating diseases and disorders including cancer and various other angiogenic-dependent diseases, vascular malfunctions, arteriovenous malformations (AVM), hemorrhagic processes and treatment of pain, in particular tumor-related pain by drug delivery and/or therapeutic embolization using microspheres. More particularly the invention relates to microspheres containing non-ionic contrast agents, to compositions comprising these microspheres, as well as methods for preparing and using such compositions for embolization therapy. The invention further relates to compositions and methods using detectable microspheres for targeted drug delivery, irrespective of whether embolization is also needed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 60/679,348 filed May 9, 2005, which is herein incorporated byreference in its entirety.

FIELD OF INVENTION

The present invention relates to compositions and methods for treatingdiseases and disorders including cancer and various otherangiogenic-dependent diseases, vascular malfunctions, arteriovenousmalformations (AVM), hemorrhagic processes and treatment of pain, inparticular tumor-related pain by drug delivery and/or therapeuticembolization using microspheres. More particularly the invention relatesto microspheres containing non-ionic contrast agents, to compositionscomprising these microspheres, as well as methods for preparing andusing such compositions for drug delivery and/or embolization therapy.Furthermore, the invention relates to compositions and methods usingdetectable microspheres for targeted drug delivery, irrespective ofwhether embolization is also needed.

BACKGROUND OF INVENTION

Therapeutic vascular occlusions (embolizations) are techniques used totreat certain pathological conditions in situ and involve the injectionof an embolic material into the vessel of concern. For example, bloodvessels which nourish a tumor are deliberately blocked by injection ofan embolic material into the vessel. Notably in the case of tumors,vascular occlusion can suppress pain, limit blood loss on the surgicalintervention to follow embolization, or even bring on a tumoral necrosisand avoid the operation.

In the case of vascular malformations, such as AVM or arteriovenousfistulas, vascular occlusion enables the blood flow to the tissues to benormalized, aids in surgery, and limits the risk of hemorrhage. Inhemorrhagic processes, vascular occlusion produces a reduction of flow,which promotes cicatrization of the arterial opening(s).

Embolization can be used in the treatment of uterine fibroids,postpartum and/post-caesarian bleeding, post-surgical vaginal bleeding,the prevention and/or treatment of hemorrhage from ectopic pregnancy,prophilatically prior to myomectomy and in obstetrical patients at highrisk for bleeding, such as those patients with placenta previa, placentaaccreta, and twin fetal death. Embolization can also be used to stopuncontrolled bleeding, or to slow bleeding prior or during surgery, andfor sealing endoleaks into aneurysm sacs. Each of the above diseases ordisorders is within the scope of the invention.

Furthermore, depending on the pathological conditions treated, drugdelivery and/or therapeutic embolization can be carried out fortemporary as well as permanent objectives.

Embolization is carried out generally by means of catheters making itpossible to position particulate occlusion agents (emboli) in thecirculatory system. For precise positioning some visual control isrequired. Therefore it is desired to use an embolic material that issuitably labeled by the addition of a contrast agent. For reducing theinterference with the catheters, solid embolic materials are preferredover liquid embolic materials, which can stick to the catheter.Microspheres have been used as a suitable solid material in passiveembolization, i.e., mechanical occlusion of particular vessels or sitesin vivo.

A further advantage of microspheres is their potential as agents fordrug delivery or for active embolization therapy. In drug delivery, themicrospheres are used as a carrier for a drug/therapeutic or activeagent, which is then released from the microspheres at the desired sitein vivo, irrespective of whether mechanical blockage is desired or not.In active embolization therapy, the microspheres have a dual function:mechanical blockage (embolization) and highly localized, in situdelivery of a therapeutic agent. This agent can be used, for example, inthe treatment of tumors with a chemotherapeutic or radiotherapeuticagent. This type of regional therapy can localize treatment at the siteof the tumor. Potential site effects and damage to healthy tissue canthus be reduced, in particular when using cytotoxic chemotherapeutic orradiotherapeutic agents. Regional administration of the drug/agent (byactive embolization or drug delivery) has the further advantage ofincreasing peak drug concentrations to the target tissue. This is notonly advantageous for the administration of chemotherapeutic orradiotherapeutic agents but also for the administration of, for example,chemotherapeutic or pain relieving drugs.

However, the type of contrast agent loaded onto the microspheres hasbeen found to alter the properties of the microspheres, such as reducingswellability of swellable materials, capacity to load additionalcomponents, such as a drug, or suitability to be injected by a catheter.Therefore, it is advantageous to provide microspheres suitable forembolization that are not only labeled but that are furthermore stillcapable of adsorbing or otherwise carrying a drug. Similarly,microspheres of the invention are useful for delivery of drugs or othertherapeutics to particular cells, tissues or organs.

Thus, there is a demonstrated need for the further development ofmicrospheres comprising a contrast agent, a drug, and/or anothertherapeutic agent which optionally can swell to sizes greater than theirinitial size. Therefore, it is an object of the present invention toprovide contrast agent-containing microspheres with superior capacitiesfor drug loading and/or delivery. It is another object of the inventionto provide contrast agent-containing microspheres that have superiorswelling properties. It is a further object of the invention to providecontrast agent-containing microspheres that have a hydrogel-likebehavior. The contrast agent-containing microspheres can be suitable inactive embolization therapy and/or in drug-delivery, and, in particular,for the treatment of angiogenesis-dependent diseases and/or relief oftumor-related pain.

SUMMARY OF INVENTION

In therapy, it is generally desirable to use microspheres that arevisible to the practitioner during administration, and that themicrospheres contain a drug which is slowly released at a lowconcentration so as to minimize the side-effects associated with thedrug. Slow release is sufficient for the desired treatment since themicrosphere is already at a location or target at which the drug is tobe delivered. Additionally, the microsphere should have superior loadingcapacities, i.e., the microspheres are able to load a maximum amount ofthe drug in the presence of the contrast agent.

The most suitable microspheres for use in active embolization and/ordrug delivery are based on hydrophilic polymers, such as hydrophilicpolymers comprising hyodroxy and/or amine groups. In some embodiments,polymers or copolymers having positively charged groups or negativelycharged groups or both can be used.

The microspheres may comprises a polymer or copolymer, such as,polyvinylalcohol (PVA), PVA-based polymers, PVA copolymers, or polymersor copolymers prepared from monomers based on acrylic acid, acrylamides, acrylates, i.e., acrylic acid esters and/or their derivatives,such as, for example, methacrylamide, methacrylate, methacrylic acid,etc. The polymers and/or copolymers may be cross-linked or notcross-linked.

In an embodiment in which acrylamides are used, the aminofunctionalities can be protonated to create positively charged groups.In embodiments in which acrylic acids are used, negatively chargedgroups can be created by deprotonating the acid functionality. Inembodiments in which acrylic esters are used, ionic groups can begenerated by hydrolyzing the ester groups. Ionic groups can also begenerated by using suitable crosslinkers, in which case the resultingpolymer or copolymer is cross-linked. The microspheres can alsoadditionally have one or more or all of the properties described below.

In certain embodiments, the drug to be delivered is water soluble. Inspecific embodiments, the drug is in the form of a salt, such as a saltselected from the group consisting of hydrochloride, potassium chloride,ammoniumchloride, sodium sulphate or potassium sulphate. Additionally,the drug may have one or more or all the properties described in thedetailed description of the invention.

It is an object of the invention to provide microspheres suitable foractive embolization therapy and/or drug delivery comprising: (a) one ormore hydrophilic or ionic polymer(s), and (b) a drug, such as a drug inthe form of a salt, wherein the microsphere has the desired slow releaseproperties of the drug and, in certain embodiments, superior drugloading capacity in the presence of a contrast agent and visibility tothe practitioner when administering the microsphere to its target.

A suitable contrast agent for the above described system is a non-ioniccontrast agent. The contrast agent may have one or more or all of theproperties described in the detailed description of the invention.

In one embodiment, the invention provides compositions and methods fordelivery of drugs, vaccines, polynucleotides, polypeptides, antibodies,polysaccharides, and/or diagnostic or imaging agents to a mammal, usingmicrospheres as a carrier. In a most preferred embodiment, the inventionprovides microspheres comprising a non-ionic contrast agent for thedelivery of at least one drug, a contrast agent, or a combinationthereof.

In one embodiment, the invention provides a substantially sphericalmicrosphere suitable for embolization and/or drug delivery, saidmicrosphere comprising: (a) a biocompatible polymeric materialcomprising PVA, and (b) a non-ionic contrast agent; wherein themicrosphere is swellable, for example, in a pharmaceutically acceptablesolution and has a diameter of from about 10 μm to about 1000 μm beforeswelling. In some embodiments, the non-ionic contrast agent is selectedfrom the group consisting of X-ray, computed tomography (CT),paramagnetic or superparamagnetic contrast agents, and, in a certainembodiment, the contrast agent contains iodine.

In another embodiment, the invention provides a substantially sphericalmicrosphere suitable for embolization and/or drug delivery, saidmicrosphere comprising: (a) a biocompatible polymeric materialcomprising PVA, (b) a non-ionic contrast agent, and/or (c) a drug,wherein the microsphere is swellable, for example, in a pharmaceuticallyacceptable solution and has a diameter of from about 10 μm to about 1000μm before swelling. In some embodiments, the non-ionic contrast agent isselected from the group consisting of X-ray, CT, paramagnetic orsuperparamagnetic contrast agents, and, in a certain embodiment, thecontrast agent contains iodine.

In a further embodiment, the invention provides a pharmaceuticalcomposition comprising: (a) substantially spherical microspheressuitable for embolization and/or drug delivery, said microspherescomprising: (i) a biocompatible polymeric material comprising PVA, (ii)a non-ionic contrast agent, and (iii) a drug, wherein the microspheresare uniform in size and have a diameter of from about 10 μm to about1000 μm; and (b) a pharmaceutically acceptable liquid. In someembodiments, the non-ionic contrast agent is selected from the groupconsisting of X-ray, CT, paramagnetic or superparamagnetic contrastagents, and, in a certain embodiment, the contrast agent containsiodine.

In another embodiment, the invention provides a pharmaceuticalcomposition comprising: (a) substantially spherical microspheressuitable for embolization and/or drug delivery, said microspherescomprising: (i) a biocompatible polymeric material comprising PVA, (ii)a non-ionic contrast agent, and (iii) a drug, wherein the microspheresare uniform in size and have a diameter of from about 10 μm to about1000 μm; and (b) a pharmaceutically acceptable liquid. In someembodiments, the non-ionic contrast agent is selected from the groupconsisting of X-ray, CT, paramagnetic or superparamagnetic contrastagents, and, in a certain embodiment, the contrast agent containsiodine.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) non-crosslinked PVA, (b) a non-ionic contrast agent, and (c) a drug;wherein the microspheres are uniform in size and have a diameter of fromabout 10 μm to about 1000 μm. In certain embodiments, the drug is achemotherapeutic or pain relieving drug.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) non-crosslinked PVA, (b) a non-ionic X-ray contrast agent, and (c) adrug; wherein the microspheres are uniform in size and have a diameterof from about 10 μm to about 1000 μm.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) non-crosslinked PVA, (b) a non-ionic contrast agent, and (c) a drugselected from the group consisting of doxorubicin, cisplatin, mitomycinC, tamoxifen, and paclitaxel; wherein the microspheres are uniform insize and have a diameter of from about 10 μm to about 1000 μm.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) crosslinked PVA, (b) a non-ionic contrast agent, and (c) a drugselected from the group consisting of doxorubicin, cisplatin, mitomycinC, tamoxifen, and paclitaxel; wherein the microspheres are uniform insize and have a diameter of from about 10 μm to about 1000 μm.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) crosslinked PVA, (b) a non-ionic X-ray contrast agent, and (c) adrug, wherein the microspheres are uniform in size and have a diameterof from about 10 μm to about 1000 m.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) crosslinked PVA, (b) a non-ionic contrast agent, and (c) a drugselected from the group consisting of doxorubicin, cisplatin, mitomycinC, tamoxifen, and paclitaxel; wherein the microspheres are uniform insize and have a diameter of from about 10 μm to about 1000 μm.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) a polyvinylalcohol-acrylic acid copolymer, (b) a non-ionic contrastagent, and (c) a drug, such as a chemotherapeutic or pain relievingdrug; wherein the microspheres are uniform in size and have a diameterof from about 10 μm to about 1000 μm. In some embodiments, themicrospheres are swellable, for example, in a pharmaceuticallyacceptable solution. In certain embodiments, the polymer is a high waterabsorbing polymer. In specific embodiments, the polyvinylalcohol-acrylicacid copolymer is a vinyl alcohol and acrylate copolymer, such as asodium acrylate polymer.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) a polyvinylalcohol-acrylic acid copolymer, (b) a non-ionic X-raycontrast agent, and (c) a drug; wherein the microspheres are uniform insize and have a diameter of from about 10 μm to about 1000 μm. In someembodiments, the microspheres are swellable, for example, in apharmaceutically acceptable solution. In certain embodiments, thepolymer is a high water absorbing polymer. In specific embodiments, thepolyvinylalcohol-acrylic acid copolymer is a vinyl alcohol and acrylatecopolymer, such as a sodium acrylate polymer.

In another embodiment, the invention provides substantially sphericalmicrospheres suitable for embolization and/or drug delivery comprising:(a) a polyvinylalcohol-acrylic acid copolymer, (b) a non-ionic contrastagent, and (c) a drug selected from the group consisting of doxorubicin,cisplatin, mitomycin C, tamoxifen, and paclitaxel; wherein themicrospheres are uniform in size and have a diameter of from about 10 μmto about 1000 μm. In some embodiments, the microspheres are swellable,for example, in a pharmaceutically acceptable solution. In certainembodiments, the polymer is a high water absorbing polymer. In specificembodiments, the polyvinylalcohol-acrylic acid copolymer is a vinylalcohol and acrylate copolymer, such as a sodium acrylate polymer.

In another embodiment, the invention provides substantially sphericalmicrospheres comprising: (a) a polyvinylalcohol-acrylic acid copolymer,(b) a non-ionic contrast agent selected from the group consisting ofiopamidol (Isovue™), iodixanol (Visipaque™), iohexol (Omnipaque™),iopromide (Ultravist™) and ioversol (Optiray™), and (c) a drug, such asa chemotherapeutic drug; preferably the drug is selected from the groupconsisting of doxorubicin, cisplatin, mitomycin C, tamoxifen, andpaclitaxel; wherein the microspheres are uniform in size and have adiameter of from about 10 μm to about 1000 μm. In some embodiments, themicrospheres are swellable, for example, in a pharmaceuticallyacceptable solution. In certain embodiments, the polymer is a high waterabsorbing polymer. In specific embodiments, the polyvinylalcohol-acrylicacid copolymer is a vinyl alcohol and acrylate copolymer, such as asodium acrylate polymer.

In a further embodiment the invention provides an injectablepharmaceutical compositions comprising the above microspheres and apharmaceutically acceptable liquid.

In a further embodiment, the invention also provides a method forpreparing a pharmaceutical composition comprising: (a) substantiallyspherical microspheres suitable for active embolization and/ordrug-delivery, said microspheres comprising (i) a biocompatiblepolymeric material comprising PVA, (ii) a non-ionic contrast agent,wherein the microspheres are uniform in size and have a diameter of fromabout 10 μm to about 1000 μm; and (b) and a pharmaceutically acceptableliquid. The method comprises contacting the microspheres having adiameter ranging from about 10 μm to about 1000 μm with a solutioncontaining a non-ionic contrast agent in a pharmaceutically acceptableliquid. In certain embodiments, the microspheres are swellable, forexample, in the pharmaceutically acceptable solution, and have adiameter of 10 μm to 1000 μm before swelling. The microspheres may beoptionally sterilized, for example, by irradiation (e.g., gamma- or betairradiation).

In another embodiment, the invention provides a method of preparing thepharmaceutical composition comprising: (a) substantially sphericalmicrospheres suitable for active embolization and/or drug delivery, saidmicrospheres comprising (i) a biocompatible polymeric materialcomprising PVA, (ii) a non-ionic contrast agent, and (iii) a drug;wherein the microspheres are swellable, for example, in apharmaceutically acceptable solution, are uniform in size, and have adiameter of from about 10 μm to about 1000 μm; and (b) apharmaceutically acceptable liquid. The method comprises: (a) contactingthe microspheres having a diameter ranging from about 10 μm to about1000 μm with a solution of a non-ionic contrast agent in apharmaceutically acceptable liquid in an amount of from about 10% toabout 90% of what would be necessary to saturate the microspheres, and(b) adding a solution of a drug in a pharmaceutically acceptablesolution until the microspheres are saturated. The microspheres may beoptionally sterilized, for example, by irradiation (e.g., gamma- or betairradiation).

In another embodiment, the invention provides a method of preparing aninjectable pharmaceutical compositions comprising microspheres, saidmethod comprising: (a) contacting swellable microspheres having adiameter ranging from 10 μm to 1000 μm, which comprise a biocompatiblepolymeric material comprising polyvinylalcohol, with a solution of adrug in an amount of from about 10 to about 90% of what would benecessary to saturate the microspheres, and (b) adding a solution of anon-ionic contrast agent in a pharmaceutically acceptable liquid untilthe microspheres are saturated. The microspheres may then be optionallysterilized, for example, by irradiation (e.g., gamma- or betairradiation).

Within another embodiment, a method is provided for active embolizationin a mammal which comprises administering to a mammal a microsphereaccording to the invention or a pharmaceutical composition according tothe invention.

Within another embodiment, a method is provided for active embolizationin a mammal which comprises administering to a mammal having anangiogenesis-dependent disease a microsphere according to the inventionor a pharmaceutical composition according to the invention.

Within another embodiment, a method is provided for drug delivery in amammal, with or without embolization, which comprises administering to amammal a microsphere according to the invention or a pharmaceuticalcomposition according to the invention.

Within another embodiment, a method is provided for drug delivery in amammal, with or without embolization, which comprises administering to amammal having an angiogenesis-dependent disease a microsphere accordingto the invention or a pharmaceutical composition according to theinvention.

Within another embodiment, a method is provided for drug delivery in amammal, with or without embolization, which comprises administering to amammal having a tumor or other form of cancer a microsphere according tothe invention or a pharmaceutical composition according to theinvention. In certain embodiments, the microsphere or pharmaceuticalcomposition is administered locally at the site of the tumor or otherform of cancer, for example, directly into a tumor mass.

In other embodiments, a method is provided for the treatment of a tumoror other cancer in a mammal, which comprises administering to a mammalhaving the tumor or other form of cancer a microsphere according to theinvention or a pharmaceutical composition according to the invention. Incertain embodiments, the microsphere or pharmaceutical composition isadministered locally at, or directly into, the site of the tumor orother form of cancer. In some embodiments, the tumor or other form ofcancer is treated by localized drug delivery. In other embodiments, thetumor or other form of cancer is treated by localized drug delivery incombination with embolization.

Within another aspect of the present invention, methods are provided fortreating tumor excision sites, comprising administering microspheresaccording to the invention or a pharmaceutical composition according tothe invention to the resection margins of a tumor subsequent toexcision, such that the local recurrence of cancer and the formation ofnew blood vessels at the site is inhibited.

Within other aspects, methods are provided for embolizing blood vesselsin nontumorigenic, angiogenesis-dependent diseases, comprisingdelivering to the vessel microspheres or a pharmaceutical compositionaccording to the invention, such that the blood vessel is effectivelyoccluded.

Within other aspects, methods are provided for treating neovasculardiseases of an organ comprising administering to a patient in needthereof microspheres according to the invention or a pharmaceuticalcomposition according to the invention such that the formation of newblood vessels is inhibited.

Within other aspects, methods are provided for treating pain related totumors comprising administering to a patient in need thereofmicrospheres according to the invention or a pharmaceutical compositionaccording to the invention. In some embodiments the pain is treated bydelivery of drug using a microsphere of the invention, either alone orin combination with embolization.

These and other aspects of the present invention will become evidentupon reference to the following detailed description and attacheddrawings. In addition, various references are set forth below which areincorporated herein by reference in their entirety.

DETAILED DESCRIPTION OF THE INVENTION

For clarity of disclosure, and not by way of limitation, the detaileddescription of the present invention is divided into the subsectionswhich follow.

Definitions

As used herein, “microspheres” means polymer or combinations of polymersmade into bodies of various sizes. The microspheres can be in any shape,although they are often in substantially spherical shape. In certainembodiments, the microspheres are sterile, either alone or when in theform of an injectable solution. The microspheres may be sterilized byany method known in the art, for example, by irradiation, such as gamma-or beta irradiation. In some embodiments, the surface of the microsphereappears smooth under less than 1000-fold magnification. The microspheresof the present invention may comprise other materials as described anddefined herein.

As used herein, “substantially spherical” generally means a shape thatis close to a perfect sphere, which is defined as a volume that presentsthe lowest external surface area. Specifically, “substantiallyspherical” in the present invention means, when viewing anycross-section of the microsphere, the difference between the majordiameter and the minor diameter is less than 20%, less than 10% or lessthan 5% depending on the embodiment used.

As used herein, The term “about” or “approximately” means within 20%,preferably within 10%, and more preferably within 5% (or 1% or less) ofa given value or range.

As used herein, “cell adhesion promoter” in the present invention meansany material that, because of their presence in or association with themicrospheres, promotes or enhances the adhesiveness of cells to thesurface of the microspheres. These materials are often proteins that areassociated with the surface of the microspheres through covalent bondsor in an interpenetrated polymeric manner.

As used herein, “therapeutic agent” in the present invention refers toany substance that provides therapeutic effects to the process ofangiogenesis-dependent diseases or biological or physiological responsesto the angiogenesis-dependent diseases. An example of a therapeuticagent is an anti-inflammation agent that prevents or reduces the effectof inflammations associated with angiogenesis-dependent diseases.

As used herein, “hydrophilic interaction” refers to molecules orportions of molecules which may substantially bind with, absorb and/ordissolve in water. This may result in swelling and/or the formation ofreversible gels.

As used herein, “hydrophobic interaction” refers to molecules orportions of molecules which do not substantially bind with, absorband/or dissolve in water.

As used herein, “swellable” microspheres refers to microspheres that arecapable of being enlarged in size, yet retain substantially the sameshape, upon certain conditions, such as contacting aqueous liquids orphysiological fluids. In certain embodiments, the swellable microspherescan be enlarged to about 15 times of their original size or to about 64times their original volume. In certain embodiments, swellablemicrospheres are enlarged to about 4 times their original size or 64times in volume upon contact with saline (0.9% sodium chloridesolution). In some embodiments “swellable” microspheres refers tomicrospheres that have the ability to absorb water. For example, incertain embodiments, the water absorption rate of a swellablemicrosphere is at least about 750 g/g. The degree of swelling can becontrolled by controlling factors such as, for example, the solvents inwhich they are suspended, and specific polymers used to make themicrospheres. In certain embodiments, the degree of crosslinking isadjusted, and in other embodiments, cross-linking is not adjusted or isnot present This property enables the microspheres to be injectedthrough needles of, for example, 18 to 30 gauge or smaller, yet beenlarged and secured at the injection site and of sufficient size toavoid or reduce the chance of being eliminated by the lymphatic orimmune system of the mammal.

As used herein, “high water absorbing polymers” refers to polymers thatcan absorb at least 5% of water by weight or that are capable ofincreasing their dry weight to about 20 times of their original weightwhen absorbing water. In some embodiments, the microspheres are“superabsorbant polymers” that can up to about 300 times, up to about400 times, up to about 500 times, up to about 600 times, up to about 700times, or up to about 750 times or more of their initial weight of aphysiological fluid. For example, 1 g of dry microspheres can absorb upto about 300 g, up to about 400 g, up to about 500 g, up to about 600 g,up to about 700 g, or up to about 750 g or more of deionized water atroom temperature (25° C.) and under atmospheric pressure.

Microspheres of the present invention, in certain embodiments, cancomprise particles that are “hydrophilic.” As used herein, the term“hydrophilic” means that the particles can dissolve in, absorb, or mixeasily with water or aqueous solutions.

A used herein, “injectable” means capable of being administered,delivered or carried into the body via syringe, catheters, needles orother means for injecting or infusing the microspheres in a liquidmedium.

As used herein, “treat,” “treatment” and “treating” refer to thereduction or amelioration of the progression, severity, and/or durationof a given disease resulting from the administration of one or moretherapies (including, but not limited to, the administration ofmicrospheres of the invention). In certain embodiments, the terms referto the reduction of pain associated with one or more diseases orconditions.

As used herein, “administer” or “administration” refers to the act ofinjecting or otherwise physically delivering a substance as it existsoutside the body (e.g., an antibody of the invention) into a patient,such as by, but not limited to, pulmonary (e.g., inhalation), mucosal(e.g., intranasal), intradermal, intravenous, intramuscular deliveryand/or any other method of physical delivery described herein or knownin the art. When a disease, or symptoms thereof, are being treated,administration of the therapy (such as the microspheres of theinvention) typically occurs after the onset of the disease or symptomsthereof. When a disease, or symptoms thereof, are being prevented,administration of the therapy (such as the microspheres of theinvention) typically occurs before the onset of the disease or symptomsthereof.

The term “effective amount” as used herein refers to the amount of atherapy (e.g., a microsphere or composition of the invention) which issufficient to reduce and/or ameliorate the severity and/or duration of agiven disease and/or a symptom related thereto.

The term “host” as used herein refers to an animal, preferably a mammal,and most preferably a human.

The term “infant” as used herein refers to a human less than 24 months,preferably less than 16 months, less than 12 months, less than 6 months,less than 3 months, less than 2 months, or less than 1 month of age.

As used herein, the term “in combination” in the context of theadministration of other therapies refers to the use of more than onetherapy. The use of the term “in combination” does not restrict theorder in which therapies are administered to a subject with aninfection. A first therapy can be administered before (e.g., 1 minute,45 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 4 hours, 6 hours,12 hours, 24 hours, 48 hours, 72 hours, 96 hours, 1 week, 2 weeks, 3weeks, 4 weeks, 5 weeks, 6 weeks, 8 weeks, or 12 weeks), concurrently,or after (e.g., 1 minute, 45 minutes, 30 minutes, 45 minutes, 1 hour, 2hours, 4 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours, 96hours, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 8 weeks, or12 weeks) the administration of a second therapy to a subject which had,has, or is susceptible to a given disease. Any additional therapy can beadministered in any order with the other additional therapies. Incertain embodiments, the microspheres of the invention can beadministered in combination with one or more therapies (e.g., therapiesthat are not microspheres of the invention that are currentlyadministered to prevent, treat, manage, and/or ameliorate a givendisease or other symptom related thereto). Non-limiting examples oftherapies that can be administered in combination with microspheres ofthe invention include analgesic agents, anesthetic agents, antibiotics,or immunomodulatory agents or any other agent listed in the U.S.Pharmacopoeia and/or Physician's Desk Reference.

As used herein, the terms “manage,” “managing,” and “management” referto the beneficial effects that a subject derives from a therapy (e.g.,microspheres of the invention), which does not result in a cure of theinfection. In certain embodiments, a subject is administered one or moretherapies to “manage” a given disease or one or more symptoms relatedthereto, so as to prevent the progression or worsening of the disease.

The term “pharmaceutically acceptable” as used herein means beingapproved by a regulatory agency of the Federal or a state government, orlisted in the U.S. Pharmacopeia, European Pharmacopeia or othergenerally recognized pharmacopeia for use in animals, and moreparticularly in humans

As used herein, the terms “prevent,” “preventing,” and “prevention”refer to the total or partial inhibition of a given disease; the totalor partial inhibition of the development or onset of disease progressionof given disease, or a symptom related thereto in a subject; the totalor partial inhibition of the progression of an given disease or asymptom related thereto.

As used herein, the terms “subject” and “patient” are usedinterchangeably. As used herein, a subject is preferably a mammal suchas a non-primate (e.g., cows, pigs, horses, cats, dogs, rats, etc.) anda primate (e.g., monkey and human), most preferably a human. In someembodiments, the subject is an infant, child, adult or elderly subject.

As used herein, the term “therapy” refers to any protocol, method and/oragent that can be used in the management, treatment and/or ameliorationof a given disease, or a symptom related thereto. In certainembodiments, the terms “therapies” and “therapy” refer to a biologicaltherapy, supportive therapy, and/or other therapies known to one ofskill in the art, such as medical personnel, useful in the management ortreatment of a given disease, or symptom related thereto.

Microspheres

In certain embodiments, the microspheres of the present invention arefluoroscopically visible. That is, in some embodiments, the microspheresare loaded with, associated with, or otherwise contain a suitablecontrast agent, such as a non-ionic contrast agent. In some embodiments,the microspheres of the invention are fluoroscopically visible andcomprise a drug. One such embodiment is a substantially sphericalPVA-containing swellable microsphere comprising a non-ionic contrastagent, and an anti-cancer drug. Another embodiment is a substantiallyspherical PVA-containing swellable microsphere comprising a non-ioniccontrast agent, and a chemotherapeutic or pain relieving drug.

In certain embodiments, the microspheres for use in the presentinvention are biocompatible, hydrophilic, substantially spherical, andnon-toxic and comprise at least one polymer. In some embodiments, thepolymer is a hydrophilic polymer. In specific embodiments, the polymeris a high water absorbing or superabsorbant polymer. In someembodiments, the microspheres, in its dry form, is swellable uponcontact or other exposure to liquids, such as water, saline solution,buffer, or physiological fluids.

In certain embodiments, the microspheres are injectable through a needleof 18 gauge or smaller and are not capable of being eliminated by theimmune or lymphatic system. In some embodiments, the polymers are coatedwith agents which promote cell adhesion. In specific embodiments, livingcells are attached to the microspheres forming layers of cells thereinor thereon that link with surrounding tissues and can enhance thelong-term stability of the beads.

The microspheres are stable in suspension, which allows the microspheresto be formulated and stored in suspension and injected with differentliquids. More specifically, the hydrophilic nature of the microspherespermits placing them in suspension, and in particular, in the form ofsterile and pyrogenic (pyrogen-free) injectable solutions, whileavoiding the formation of aggregates or adhesion to the walls of storagecontainers and implantation devices, such as catheters, syringes,needles, and the like.

Microspheres of the invention can be implanted, such as by injection, invarious locations of the body. The polymeric material for use in thepresent invention is non-toxic to tissues and cells and isbiocompatible, i.e. generally does not cause inflammation. Themicrospheres can maintain their general shape and position onceimplanted at a desired site. The microspheres of the present inventionare compressible and, in specific embodiments, can be injected throughneedles of 18 gauge or smaller.

These properties can be achieved through two steps. First, the size ofthe microspheres before injection can be carefully controlled by usingappropriate solvents, salt concentration and pH level, and determiningthe final size of the microsphere upon saturation. With the final sizeand the amount of liquid necessary to achieve saturation having beendetermined, the microspheres before injection can be adjusted to eitherremain in their original size or swell to a certain degree upon contactwith the solvent. The swelling depends on the solvent used, including pHand ionic strength of the solvent. The pre-injection swelling iscontrolled so that the microspheres are easily injectable through 18gauge or smaller needles (e.g., 30 gauge). Second, after injection andupon contacting with tissues at injection site, the microspheres canfurther swell into predetermined size or retain their pre-injectionsize, either of which size will allow the microspheres to be secured atthe site of injection. In certain embodiments, the microspheres alsoachieve an embolization effect. The degree of pre-injection swelling,and thus the after injection swelling, can be determined by theparticular microspheres used and the nature and location of thedeficiencies being treated and the solvent used for swelling.

The microspheres for use in the present invention are flexible, suchthat they can easily pass into and through injection devices and smallcatheters without being permanently altered, but the microspheres arealso resistant to the muscle contraction stress generated during andafter the implantation process. The microspheres are also thermallystable which allows for easy, convenient sterilization, and roomtemperature, refrigerated or frozen storage.

In certain embodiments, the microspheres are substantially spherical,i.e., they have a shape that is close to a perfect sphere, which isdefined as a volume that presents the lowest external surface area. Insome embodiments, the surface of the microsphere appears smooth underless than 1000-fold magnification.

The microspheres are swellable in a pharmaceutically acceptable liquid,such as water, buffer solutions, saline, body liquids, aqueous saltsolutions. In some embodiments, the dry microspheres can swell to about2 times, about 5 times, or about 10 times of the dry microspherediameter when saturated with a liquid, such as deionized water at roomtemperature (25° C.).

In certain embodiments, the dry microspheres are high water absorbingpolymers and/or superabsorbant polymers. As used herein,“superabsorbant” means that 1 g dry microsphere can absorb up to about300 g, up to about 500 g, or up to about 700 g of deionized water atroom temperature (25° C.) and under atmospheric pressure.

In certain embodiments, the microspheres are uniform in size. This meansthat the difference in diameter between individual microspheres is fromabout 0 μm to about 100 μm, from about 0 μm to about 50 μm, or fromabout 0 μm to about 25 μm. In some embodiments, the microspheres havedifferences in diameter of 100 μm or less, about 50 μm or less, about 25mm or less, about 10 mm or less or about 5 μm or less.

An individual microsphere according to the invention can have a diameterranging from about 10 μm to about 1000 μm, from about 10 μm to about 400μm, from about 50 μm to about 100 μm, from about 100 μm to about 150 μm,from about 150 μm to about 200 μm, or from about 100 μm to about 400 μmin its dry form, i.e. before swelling. As used herein, “dry”microspheres are microspheres that have less than about 10%, less thanabout 7%, less than about 5% (such as about 4%-5%), less than about 3%or less than about 1% of a liquid, such as water. Dry microspheres canbe in the form of a powder. In some embodiments, the diameter of themicrosphere before swelling is from about 40 μm to about 1000 μm, about40 μm to about 400 μm, about 50 μm to about 300 μm, about 50 μm to about200 μm, about 70 μm to about 120 μm, about 10 μm to about 400 μm, about10 μm to about 200 μm, about 10 μm to about 120 μm, about 10 μm to about50 μm, about 53 μm to about 106 μm, about 106 μm to about 150 μm, about150 μm to about 212 μm, about 200 μm to about 250 μm, about 212 μm toabout 250 μm, about 250 μm to about 300 μm, about 300 μm to about 350μm, about 350 μm to about 400 μm, about 400 μm to about 450 μm, or about450 μm to about 500 μm.

Most preferably, the microspheres are in a population wherein greaterthan 68% have a diameter of ±20% of the mean, ±10% of the mean, or ±5%of the mean diameter. In one embodiment, the microspheres are in apopulation wherein greater than 75% have a diameter of ±20% of the mean,±10% of the mean or ±5% of the mean diameter. For example, in oneembodiment the microspheres have a diameter between about 200 μm toabout 250 μm or about 212 μm to about 250 μm. In certain embodiments,the microspheres have a mean diameter of 225 μm, and, in someembodiments, 75% of the population has a range of ±10% of the 225 μmmean diameter (i.e., 225 μm±22.5 μm).

In specific embodiments, the dry microspheres swell when contacted witha pharmaceutically acceptable liquid. In their swollen or partiallyswollen form (i.e. when the microspheres are no longer a dry powder butare instead in the form of a suspension or a hydrogel), the microspherescan have a diameter ranging from about 40 μm to about 2000 μm, about 200μm to about 2000 μm, about 500 μm to about 1500 μm, or about 1000 μm toabout 1500 μm. The diameter of the microspheres can be determined, forexample, microscopically. The diameter of the microspheres can also bedetermined by any one of a number of methods known to those skilled inthe art, such as laser systems. In some embodiments, the drymicrospheres swell to about 2 times, about 3 times, about 4 times, about5 times, or about 6 times the diameter of the dry microsphere prior toswelling. Thus, in some embodiments, the diameter of the swollenmicrospheres may be from about 2 times to about 6 times the diameter ofany of the dry microsphere diameters, or ranges of diameters thereof,disclosed elsewhere herein.

It is an aspect of the invention to provide microspheres containing (a)a polymeric material, (b) a non-ionic contrast agent, and (c) a drug,such as a drug in the form of a salt. In certain embodiments, thepolymeric material comprises a polymer or copolymer selected from thegroup consisting of polyvinylalcohol, polyacrylamide, or polyacrylate.Preferably, the polymeric material further comprises charged groups,such as positively charged or negatively charged groups, which may bepresent, for example, as functional groups of a copolymer or acrosslinking unit or may be introduced by chemical modification of thepolymers. The ionic group(s) may be positively charges group(s),negatively charged group(s) or both. In certain embodiments, the ionicgroup can be a protonated amino group or a deprotonated carboxylic acidgroup (e.g., hydrolyzed ester groups).

The polymeric material of the present invention includes, but is notlimited to, an acrylic polymer or copolymer, a polyacrylamide polymer orcopolymer, or a polyvinlyacetate polymer or copolymer. The polymericmaterial can also contain a polylactic acid polymer or copolymer, apolyanhydride polymer or copolymer, a polyacrylonitrile polymer orcopolymer, a polysaccharide polymer or copolymer, and mixtures thereof.

In some embodiments, the polymeric material comprises PVA. Morepreferably, the polymeric material comprises a PVA copolymer. Thepolymeric material may also comprise a polyacrylate polymer orcopolymer. In certain embodiments, the polymeric material is aPVA-polyacrylate copolymer. In other embodiments, the polymeric materialis a PVA-sodium acrylate copolymer.

Another suitable polymer is an acrylic acid polymer or copolymer. Yetanother suitable material is an acrylamide polymer or copolymer.

The polymeric material may include one or more polymer(s), one or morepolymer mixture(s), a copolymer, copolymer mixtures, orpolymer-copolymer mixtures.

In certain embodiments, the polymeric material is substantiallyhydrophilic. This means the microspheres contain at least onehydrophilic polymer or copolymer but it may also include the presence ofhydrophobic polymers or copolymers as long as the overall characteristicof the microsphere are substantially hydrophilic rather thanhydrophobic. In some embodiments, the hydrophilic polymer is a polymercontaining —OH and/or —NH₂ groups. In other embodiments, the hydrophilicpolymer contains ionic groups.

Suitable polymers the polymeric material may contain are polyvinylalcohol, polyacrylate, polyacrylamide, polyacrylonitrile, polyvinylacetate, or polyvinyl acetals.

A polymer according to the invention is a polymer containing polyvinylalcohol or polyvinyl acetate units and acrylamide groups.

Another polymer according to the invention is a polymer containingpolyvinyl alcohol or polyvinyl acetate units and acrylic acid in itsprotonated or deprotonated forms including counterions.

In one embodiment, the polyacrylate is a hydrolyzed polyacrylic acidester. Examples of polyacrylates are, without limitation, sodiumpolyacrylate, potassium polyacrylate, ammonium polyacrylate or mixturesthereof.

The polymer material, such as PVA, can be crosslinked or notcrosslinked.

In some embodiments, when a polymeric material is used that comprises aPVA-polyacrylate copolymer, the ratio of PVA units to polyacrylate unitsis from about 2 to 8 (about 2:8) to about 8 to 2 (about 8:2). In someembodiments, the ratio of acrylate moieties to vinylalcohol moieties isfrom about 2 to 8 to about 8 to 2, such as, for example in a sodiumacrylate and vinyl alcohol copolymer.

When the PVA is cross-linked, the polymeric material can comprise fromabout 0.5% to 20% by weight of crosslinkers. The amount of crosslinkerscan vary from about 0% to about 5%, about 10%, about 15%, about 20%,about 25%, about 30%, about 40%, about 50%, about 60%, about 70%, about80%, or about 90% or higher of the polymer units.

In some embodiments, the microsphere comprises about 1% to about 95% byweight of polyvinlylalcohol. In certain embodiments, the microspherecomprises polyvinylalcohol in an amount selected from the groupconsisting of about 1% by weight, about 5% by weight, about 10% byweight, about 15% by weight, about 20% by weight, about 25% by weight,about 30% by weight, about 35% by weight, about 40% by weight, about 45%by weight, about 50% by weight, about 55% by weight, about 60% byweight, about 65% by weight, about 70% by weight, about 75% by weight,about 80% by weight, about 85% by weight, about 90% by weight, and about95% by weight.

In some embodiments, the hydrophilic acrylic monomer in the preparationof a PVA copolymer is selected from the group consisting of acrylamideand its derivatives, methacrylamide and its derivatives, acrylic esteracid and/or hydroxymethylmethacrylate. In some embodiments, theresulting copolymer is saponified.

Crosslinking can be carried out by using bifunctional or multifunctionalmonomers in the synthesis of the polymeric material. Alternatively, thepolymer can also be crosslinked after its synthesis, for example, bytreating the polymer (such as, for example, PVA) with an aldehyde, suchas glutaraldehyde, formaldehyde, and the like. Examples of bifunctionalmonomers that can be used for the preparation of crosslinked copolymers,include, but are not limited to mono- or bifunctional acrylamides, e.g.,the N,N′-methylene-bis-acrylamide, N′,N′-diallylacryliamide orglyoxal-bis-acrylamide.

In some embodiments, the microspheres according to the inventioncomprise a non-ionic contrast agent. The contrast agent can be loaded onthe microsphere, associated with the microsphere, absorbed by, adsorbedby or otherwise contained in or on the microsphere. Alternatively, thecontrast agent is a carrier solution for the microsphere. Preferably,the contrast agent is loaded within the microsphere. In otherembodiments, the microspheres do not comprise a contrast agent, such asa non-ionic contrast agent.

The non-ionic contrast agent according to the invention can be an X-ray,CT, MRI contrast agent, or a combination thereof. The contrast agent canbe paramagnetic or superparamagnetic. In some embodiments, the contrastagent according to the invention is an X-ray contrast agent (alsoreferred to as fluoroscopic agent or radio-opaque) or a CT contrastagent. In certain embodiments, the agent contains iodine. The non-ioniccontrast agents can be monomeric, dimeric, or polymeric.

Examples of non-ionic contrast agents according to the invention are,without limitation, metrizamide, iopamidol (Isovue™ or Iopamiron™),iodixanol (Visipaque™), iohexol (Omnipaque™), iopromide (Ultravist™),iobtiridol, iomeprol, iopentol, iopamiron, ioxilan, iotrolan,gadodiamide, gadoteridol, iotrol, ioversol (Optiray™) or combinationsthereof. In certain embodiments, the contrast agent is not iopamidol. Inother embodiments, the microsphere comprises iopamidol, at least oneadditional non-ionic contrast agent, and/or at least one drug. Inspecific embodiments, non-ionic contrast agents that can be used areiodixanol, iohexal, iopromide, and ioversol. In another embodiment, thenon-ionic contrast agent is gadodiamide or gadoteridol.

The microspheres according to the invention can be prepared by firstsynthesizing microspheres composed of the polymeric material. Examplesfor such microspheres are provided in, for example, EP 1 128 816 B1; WO01/72281; JP 6-56676, JP 54-37994; and U.S. Pat. Nos. 4,320,040 and4,367,323, which are incorporated herein by reference.

Microspheres can be prepared by suspension polymerization, drop-by-droppolymerization or any other method known to the skilled artisan. Themode of microsphere preparation selected will usually depend upon thedesired characteristics, such as microsphere diameter and chemicalcomposition, for the resulting microspheres. The microspheres of thepresent invention can be made by standard methods of polymerizationdescribed in the art (see, e.g., E. Boschetti, Microspheres forBiochromatography and Biomedical Applications. Part I, Preparation ofMicrobeads, In: Microspheres Microencapsulation and Liposomes, JohnWiley & Sons, Arshady R., Ed., vol. 2, p. 171-189 (1999), which isincorporated herein by reference). In some embodiments, microspheres areprepared starting from an aqueous solution of monomers and optionallycontaining cell adhesion agents, such as collagen or gelatin (gelatin isa denatured collagen). The solution can then mixed with anon-aqueous-compatible solvent to create a suspension of droplets, whichare then turned into solid gel by polymerization of monomers by means ofappropriate catalysts. Microspheres can then be collected by filtrationor centrifugation, washed, and optionally sterilized. Since emulsion orsuspension polymerization starts from dispersed droplets, sphericalmicrospheres will be obtained after polymerization. The stirring speeddetermines the size of the droplets formed. Thus, the size of theresulting microspheres can be controlled by the stirring speed usedduring polymerization. In certain embodiments, the stirring speeds rangefrom about 100 RPM to about 250 RPM, such as about 100 RPM, about 125RPM, about 150 RPM<about 200 RPM, about 225 RPM, or about 250 RPM.

Cell adhesion promoters or marking agents can be optionally introducedon or within microspheres by chemical coupling procedures well known inaffinity chromatography, referred to by the term “ligandimmobilization.” Another method of introduction is by diffusion withinthe gel network that constitutes the microsphere and then trapping thediffused molecules in place by precipitation or chemical cross-linking.

The microspheres of the invention can also be obtained by standardmethods of polymerization described in the art such as French Patent2,378,808, U.S. Pat. Nos. 5,648,100, 5,635,215 and 4,480,044, each ofwhich is incorporated herein by reference. In general, thepolymerization of monomers in solution is carried out at a temperatureranging between about 0° C. and about 100° C. and between about 40° C.and about 60° C., in the presence of a polymerization reactioninitiator.

The polymerization initiator is advantageously chosen among the redoxsystems.

It is also possible to use combinations of an alkali metal persulfatewith N,N, N′, N′tetramethylethylenediamine or withdimethylaminopropionitrile, organic peroxides, such as benzoyl peroxidesor 2,2′-azo-bis-isobutyronitrile. The quantity of initiator used can beadapted by one skilled in the art to the quantity of monomers and therate of polymerization sought. Polymerization can be carried out in massor in emulsion or suspension.

In the case of a mass polymerization, the aqueous solution containingthe different dissolved constituents and the initiator undergoespolymerization in an homogeneous medium. This makes it possible toaccess a lump of aqueous gel which can then be separated intomicrospheres, by passing, for example, through the mesh of a screen.

In specific embodiments, the method of preparation is by emulsion orsuspension polymerization, which makes it possible to directly accessspherical microspheres of a desired size. For example, an aqueoussolution containing the different dissolved constituents (e.g.,different monomers and optional cell adhesion agents), can be mixed bystirring, with a liquid organic phase that is not miscible in water, andoptionally in the presence of an emulsifier. The rate of stirring can beadjusted so as to obtain an aqueous phase emulsion in the organic phaseforming drops of desired diameter. Polymerization can then be started byaddition of the initiator. Polymerization can be accompanied by anexothermic reaction and its development can then be followed bymeasuring the temperature of the reaction medium.

It is possible, in some embodiments, to use as organic phase vegetableor mineral oils, certain petroleum distillation products, chlorinatedhydrocarbons, or a mixture of these different solutions.

Furthermore, when the polymerization initiator includes severalcomponents (redox system), it is possible to add one of them in theaqueous phase before emulsification.

The microspheres thus obtained can then be recovered by cooling,decanting and filtration. The microspheres can then be separated by sizecategory, for example, by using a mesh or sieve of a particular size,and washed to eliminate any trace of secondary product.

The polymerization stage can be followed by a stage of reticulation ofthe cell adhesion agent and possibly by a marking agent stage in thecase of microspheres rendered identifiable by grafting after synthesis.

The microspheres can then optionally be contacted with a solutioncontaining a contrast agent, such as a non-ionic contrast agent. If themicrospheres are to be also loaded with a drug, the loading with thecontrast agent is not carried out to complete saturation. For thispurpose, the amount of liquid the microspheres can absorb is determinedfirst. Then dry microspheres are saturated with about 10%, about 20%about 30%, about 40%, about 50%, or about 60% up to about 70% or about80% by weight of the amount of solution that is necessary for completesaturation by the contrast agent containing solution. Then themicrospheres can be loaded with a solution comprising one or more drugsor other agents to partial or complete saturation. Alternatively, themicrospheres may first be loaded with a drug solution to partial orcomplete saturation, and subsequently (or simultaneously) loaded with acontrast agent.

As discussed elsewhere herein, it is possible to carry out the loadingonly to a fraction of the solution that is necessary for completesaturation and allow for complete saturation (swelling) within thetissue site for which the microspheres are intended to be implanted,injected, or otherwise administered.

Therefore, the microspheres can be administered in the methods describedbelow already loaded with the drug, or also unloaded or only partiallyloaded prior, simultaneously or subsequently to the administration ofthe drug solution. When the microspheres and drug are administered, forexample, simultaneously, separately, or in sequence, kits comprising (a)microspheres, (b) contrast agent and (c) one or more drugs arecontemplated.

In specific embodiments, 100 mg of dry microspheres according to theinvention can be loaded with from about 4 ml to about 12 ml, preferablyabout 5 ml to about 10 ml of saline solution (0.9% wt of NaCl).

Typically, the microspheres according to the invention, can be loadedwith from about 1 mg to about 800 mg, about 10 mg to about 400 mg, orabout 20 mg to about 300 mg of a drug per 100 mg of dry microspheres.

Typically, the microspheres can be loaded with a contrast agent, such asa nonionic contrast agent (e.g., an iodine-containing contrast agent),of from about 100 mg to about 1500 mg iodine per 100 g of drymicrospheres.

The microspheres can be loaded with from about 100 mg to about 1500 mgiodine per mg of dry microspheres with an iodine-containing contrastagent and from 1 to about 800 mg, about 10 to about 400 mg, about 20 mgto about 300 mg of a drug per 100 mg dry microsphere.

The amount of loading can be determined by adding a known solution ofthe material to be loaded to a known amount (e.g., 100 mg) of drymicrospheres. The solution is added until saturation is reached, i.e.until a supernatant is formed. The supernatant is then separated andanalyzed for the amount of loading material. This amount is thensubtracted from the total amount of the material used for loading togive the amount of material loaded on the microsphere.

Pharmaceutical Compositions

The invention also relates to pharmaceutical compositions comprising anyof the microspheres described above and a pharmaceutically acceptableliquid or other biocompatible carrier. The compositions can be in theform of a suspension, a hydrogel, or an emulsion. The composition canalso be a suspension of said microspheres in said liquid. In someembodiments, the compositions are sterile.

The pharmaceutically acceptable liquid can be, without limitation,saline, a buffer-solution, water, an isotonic solution, a biologicalfluid or a mixture thereof. The liquid can also be a salt solution,preferably composed of cations selected from the group consisting ofsodium, potassium, calcium, magnesium, iron, zinc, and ammonium, forexample, in an amount of from about 0.01 M to about 5 M.

The composition can comprise the microspheres in an amount from about10% to about 90% by weight and the liquid (or other biocompatiblecarrier) in an amount from about 10% to about 90% by weight. Thecomposition can also comprise the microspheres in an amount from about10% to about 50% by weight and the liquid (or other biocompatiblecarrier) in an amount from about 50% to about 90% by weight.

In some embodiments, the biocompatible carrier is an aqueous-basedsolution, a hydro-organic solution, an organic solution, a non-aqueoussolution, or a mixture thereof. In certain embodiments, thebiocompatible carrier comprises a salt composed of cations, such assodium, potassium, calcium, magnesium, iron, zinc, ammonium, andmixtures thereof, for example, in an amount of from about 0.01 M toabout 5 M.

The compounds loaded into or onto the microspheres can be released invivo due to physiological processes. Release of the drug or other agentloaded onto the microspheres can be influenced by pH and saltconcentrations. For example, drug release can be accelerated byestablishing pH changes or changes in ionic strength in the environmentsurrounding the microspheres. For example, drug release of doxorubicincan be released more slowly at a pH of about 7.5 than at a pH of about5.3. Determination of such optimal drug-release conditions can easily bedetermined by those skilled in the art.

In some embodiments, the drug is released over a certain number ofhours, days, or weeks. In one embodiment, about 10%, about 15%, about20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%,about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about85%, about 90%, about 95%, or about 100% of the drug has been releasedfrom the microsphere after a certain period of time, for example, afterabout 3 hours, about 6 hours, about 12 hours, about 18 hours, or afterabout 1 day, about 2 days, about 3 days, about 4 days, about 5 days,about 6 days, or after about 1 week, about 2 weeks, about 3 weeks, about4 weeks, about 5 weeks, about 6 weeks, about 7 weeks, about 8 weeks,about 9 weeks, or about 10 weeks or longer. Drug release properties willdepend, in part, on the properties of the specific drug used, but willbe readily determinable by those skilled in the art.

In some embodiments, the drug is released from the microsphere over acertain number of days or weeks. In one embodiment more than about 1%but less than about 5% of the drug has been released within a period ofabout 72 hours, a period of about 96 hours, a period of within a week, aperiod of within two weeks, or a period of within four weeks.

In another embodiment, more than about 1% but less than about 15% of thedrug has been released within a period of about 72 hours, a period ofabout 96 hours, a period of within a week, a period of within two weeks,and a period of within four weeks.

In yet another embodiment, more than about 1% but less than about 20% ofthe drug has been released within a period of about 72 hours, a periodof about 96 hours, a period of within a week, a period of within twoweeks, and a period of within four weeks.

In yet another embodiment, more than about 1% but less than about 25% ofthe drug has been released within a period of about 72 hours, a periodof about 96 hours, a period of within a week, a period of within twoweeks, and a period of within four weeks.

In yet another embodiment, more than about 1% but less than about 30% ofthe drug has been released within a period of about 72 hours, a periodof about 96 hours, a period of within a week, a period of within twoweeks, and a period of within four weeks.

The release as described above can be measured in vitro in the presenceof 0.9% saline (NaCl solution) at room temperature (25° C.) whilestirring. A typical release measurement is described in Example 5.

Methods of Treatment

The present invention provides compositions and methods suitable fortreating tumors or other cancers, non-tumorigenic angiogenesis-dependentdiseases, or pain, such as pain related to the presence of a tumor orother cancer. Such cancers include, without limitation, liver, ovarian,breast, kidney, lung, pancreatic, thyroid, prostate, uterine, skincancer, head and neck tumors, breast tumors, and Kaposi's sarcoma, andsuperficial forms of bladder cancer. The method of treatment may be theresult of localized (or systemic) drug delivery released from thedrug-loaded microspheres, either alone or in combination with emboliceffects of the microspheres (“active embolization). In certainembodiments, drug-loaded microspheres of the invention are administeredto a site-specific location other than a blood vessel (e.g., directlyinto a tumor mass), and no vessel embolization occurs.

In addition to cancer, however, numerous other non-tumorigenicangiogenesis-dependent diseases which are characterized by the abnormalgrowth of blood vessels can also be treated with the microspheres orpharmaceutical compositions according to the invention. Representativeexamples of such nontumorigenic angiogenesis-dependent diseases include,without limitation, hypertrophic scars and keloids, proliferativediabetic retinopathy, rheumatoid arthritis, arteriovenous malformations,atherosclerotic plaques, delayed wound healing, hemophilic joints,nonunion fractures, Osier-Weber syndrome, psoriasis, pyogenic granuloma,scleroderma, tracoma, menorrhagia and vascular adhesions.

Similarly, the microspheres and compositions of the invention can beused to deliver drugs to various cells, tissues or organs in needthereof. For example, the microspheres and compositions can be used totreat tumors or cancers, inflammatory diseases or other diseasesassociated with inflammation, or symptoms thereof.

It should be understood that the patients suitable for passiveembolization, active embolization or drug delivery with the microspheresaccording to the invention include humans and animals, preferably humansincluding male and female infants, children, and adults, including theelderly. Patients at risk for, or currently afflicted with,hepatocellular diseases, such as hepatitis or liver cancer, are aparticularly preferred patient population, for example Caucasian orAsian (e.g., including, but not limited to, people of Japanese heritage)human patients, 18 to 75 years of age. In some embodiments, the patientsare 25-75, 25-50, 50-75, or 18-25 years of age. In one embodiment, thepatient is less than 18 years of age (e.g., 1-5, 5-10, 10-15, 15-18years of age). In another embodiment, the patient is older than 75 yearsof age.

In some embodiments, the microspheres of the invention are used in thetreatment, management, or prevention of hepatocellular disease in apatient. In one embodiment, the patient is Child-Pugh class A. Inanother embodiment, the patient is Child-Pugh class B. In yet otherembodiments, the patient is Child-Pugh class C. The Child-Pughclassification is well known in the art, see, e.g., Child and Turcotte(1964) Surgery and portal hypertension, In: The liver and portalhypertension (Edited by: Child CG). Philadelphia, Saunders 1964, 50-64;which was later modified by Pugh et al. Transection of the esophagus inbleeding oesophageal varices (1973) Br. J. Surg. 60:648-652. In someembodiments, the patient is infected with Hepatitis C virus.

The microspheres and pharmaceutical compositions according to theinvention can be used in passive embolization therapies and in activeembolization therapies. The microspheres can also be used as deliverysystems, e.g., as drug-delivery systems, with or without embolization.

The microspheres can contain a contrast agent, such as a non-ioniccontrast agent, and at least one (e.g., one, two, three, four or more)drug(s) or other agent(s). Such a drug can be any one or more of ananti-neoplastic drug, anti-angiogenesis drug, anti-fungal drug,anti-viral drug, anti-inflammatory drug, anti-bacterial drug, acytotoxic drug, a chemotherapeutic or pain relieving drug and/or ananti-histamine drug. The drug may also be, for example, any one or moreof hormones, steroids, vitamins, cytokines, chemokines, growth factors,interleukins, enzymes, anti-allergenic agents, circulatory drugs,anti-tubercular agents, anti-anginal agents, anti-protozoan agents,anti-rheumatic agents, narcotics, cardiac glycoside agents, sedatives,local anesthetic agents, general anesthetic agents, and combinationsthereof. When used for the treatment of pain, the microspheres accordingto the invention are preferably loaded with a pain relieving drug.

In one embodiment, the microsphere comprises an anti-angiogenic oranti-neoplastic drug. In another embodiment, the microsphere comprises achemotherapeutic or pain relieving drug. In some embodiments, themicrosphere comprises one or more anti-neoplastic drugs and one or morechemotherapeutic or pain relieving drugs.

Examples of anti-angiogenic or anti-neoplastic drugs include, withoutlimitation, alkylating agents, nitrogen mustards, antimetabolites,gonadotropin releasing hormone antagonists, androgens, antiandrogens,antiestrogens, estrogens, and combinations thereof. Specific examplesinclude but are not limited to actinomycin D, aldesleukin, alemtuzumab,alitretinoin, allopurinol, altretamine, amifostine, aminoglutehimide,amphotercin B, amsacrine, anastrozole, ansamitocin, arabinosyl adenine,arsenic trioxide, asparaginase, aspariginase Erwinia, BCG Live,benzamide, bevacizumab, bexarotene, bleomycin, 3-bromopyruvate,busulfan, calusterone, capecitabine, carboplatin, carzelesin,carmustine, celecoxib, chlorambucil, cisplatin, cladribine,cyclophosphamide, cytarabine, cytosine arabinoside, dacarbazine,dactinomycin, darbepoetin alfa, daunorubicin, daunomycin, denileukindiftitox, dexrazoxane, dexamethosone, docetaxel, doxorubicin,dromostanolone, epirubicin, epoetin alfa, estramustine, estramustine,etoposide, VP-16, exemestane, filgrastim, floxuridine, fludarabine,fluorouracil (5-FU), flutamide, fulvestrant, demcitabine, gemcitabine,gemtuzumab, goserelin acetate, hydroxyurea, ibritumomab, idarubicin,ifosfamide, imatinib, interferon (e.g., interferon α-2a, interferonα-2b), imiotecan, letrozole, leucovorin, leuprolide, lomustine,meciorthamine, megestrol, melphalan (e.g., PAM, L-PAM or phenylalaninemustard), mercaptopurine, mercaptopolylysine, mesna, mesylate,methotrexate, methoxsalen, mithramycin, mitomycin, mitotane,mitoxantrone, nandrolone phenpropionate, nolvadex, oprelvekin,oxaliplatin, paclitaxel, pamidronate sodium, pegademase, pegaspargase,pegfilgrastim, pentostatin, pipobroman, plicamycin, porfimer sodium,procarbazine, quinacrine, raltitrexed, rasburicase, riboside, rituximab,sargramostim, spiroplatin, streptozocin, tamoxifen, tegafur-uracil,temozolomide, teniposide, testolactone, tioguanine, thiotepa, tissueplasminogen activator, topotecan, toremifene, tositumomab, trastuzumab,treosulfan, tretinoin, trilostane valrubicin, vinblastine, vincristine,vindesine, vinorelbine, zoledronate, salts thereof, or mixtures thereof.

In some embodiments, the platinum compound is spiroplatin, cisplatin, orcarboplatin. In specific embodiments, the drug is cisplatin, mitomycin,paclitaxel, tamoxifen, doxorubicin, tamoxifen, or mixtures thereof.

Other anti-angiogenic or anti-neoplastic drugs include, but are notlimited to AGM-1470 (TNP-470), angiostatic steroids, angiostatin,antibodies against avβ3, antibodies against bFGF, antibodies againstIL-1, antibodies against TNF-α, antibodies against VEGF, auranofin,azathioprine, BB-94 and BB-2516, basic FGF-soluble receptor,carboxyamido-trizole (CAI), cartilage-derived inhibitor (CDI), chitin,chloroquine, CM 101, cortisone/heparin, cortisone/hyaluroflan,cortexolone/heparin, CT-2584, cyclophosphamide, cyclosporin A,dexamethasone, diclofenac/hyaluronan, eosinophilic major basic protein,fibronectin peptides, Glioma-derived angiogenesis inhibitory factor(GD-AIF), GM 1474, gold chloride, gold thiomalate, heparinases,hyaluronan (high and low molecular-weight species),hydrocortisonelbeta-cyclodextran, ibuprofen, indomethacin,interferon-alpha, interferon gamma-inducible protein 10,interferon-gamma, IL-1, IL-2, IL-4, IL-12, laminin, levamisole,linomide, LM609, martmastat (BB-2516), medroxyprogesterone,methotrexate, minocycline, nitric oxide, octreotide (somatostatinanalogue), D-penicillamine, pentosan polysulfate, placentalproliferin-related protein, placental RNase inhibitor, plasminogenactivator inhibitor (PAIs), platelet factor-4 (PF4), prednisolone,prolactin (16-kDa fragment), proliferin-related protein, prostaglandinsynthase inhibitor, protamine, retinoids, somatostatin, substance P,suramin, SU1O1, tecogalan sodium (05-4152),tetrahydrocortisol-sthrombospondins (TSPs), tissue inhibitor ofmetalloproteinases (TIMP 1, 2, 3), thalidomide, 3-aminothalidomide,3-hydroxythalidomide, metabolites or hydrolysis products of thalidomide,3-aminothalidomide, 3-hydroxythalidomide, vitamin A and vitreous fluids.In another preferred embodiment, the anti-angiogenic agent is selectedfrom the group consisting of thalidomide, 3-aminothalidomide,3-hydroxythalidomide and metabolites or hydrolysis products ofthalidomide, 3-aminothalidomide, 3-hydroxythalidomide. In a preferredembodiment, the anti-angiogenic agent is thalidomide. The aboveanti-angiogenic agents are disclosed in U.S. Pat. Nos. 5,593,990;5,629,327; and 5,712,291; Norrby, APMIS, 1997, 105:417-437; O'Reilly,Investigational New Drugs, 1997, 15:5-13; and J. Nat'l Cancer Instit.,1996, 88(12):786-788, the contents of which are incorporated herein byreference.

Examples of pain reliving drugs are, without limitation, analgesics oranti-inflammatories, such as non-steriodal anti-inflammatory drugs(NSAID), ibuprofen, ketoprofen, dexketoprofen, phenyltoloxamine,chlorpheniramine, furbiprofen, vioxx, celebrex, bexxstar, nabumetone,aspirin, codeine, codeine phosphate, acetaminophen, paracetamol,xylocalne, and naproxin.

In some embodiments, the pain relieving drug is an opioid. Opioids arecommonly prescribed because of their effective analgesic, or painrelieving, properties. Among the compounds that fall within this classinclude narcotics, such as morphine, codeine, and related medications.Other examples of opioids include oxycodone, propoxyphene, hydrocodone,hydromorphone, and meperidine.

Other compounds, drugs, or other agents for which the microspheresaccording to the invention can be used as delivery systems, either withor without embolization, are listed, without limitation, below.

Blood Products:

Blood products, include, for example, without limitation,erythropoietin, parenteral iron, hemin, and hematoporphyrins and theirderivatives.

Biological Response Modifiers:

Biological response modifiers, include, for example, without limitation,muramyldipeptide, muramyltripeptide, lymphokines (e.g., bacterialendotoxin such as lipopolysaccharide, macrophage activation factor),sub-units of bacteria (such as Mycobacteria, Corynebacteria), thesynthetic peptide, N-acetyl-muramyl-L-alanyl-Disoglutamine, andprostaglandins.

Anti-Fungal Agents:

Anti-fungal agents, include, for example, without limitation,ketoconazole, nystatin, griseofulvin, flucytosine (5-fc), miconazole,amphotericin B, ricin, and β-lactam antibiotics (e.g., sulfazecin).

Hormones and Steroids:

Hormones and steroids, include, for example, without limitation, growthhormone, melanocyte stimulating hormone, adrenocortiotropic hormone,dexamethasone, dexamethasone acetate, dexamethasone sodium phosphate,cortisone, cortisone acetate, hydrocortisone, hydrocortisone acetate,hydrocortisone cypionate, hydrocortisone sodium phosphate,hydrocortisone sodium succinate, prednisone, prednisolone, prednisoloneacetate, prednisolone sodium phosphate, prednisolone tebutate,prednisolone pivalate, triamcinolone, triamcinolone acetonide,triamcinolonehexacetonide, triamcinolone acetate, methylprednisolone,methylprednisolone acetate, methylprednisolone sodium succinate,flunsolide, beclomethasone dipropionate, betamethasone sodium phosphate,betamethasone, vetamethasone disodium phosphate, vetamethasone sodiumphosphate, betamethasone acetate, betamethasone disodium phosphate,chloroprednisone acetate, corticosterone, desoxycorticosterone,desoxycorticosterone acetate, desoxycorticosterone pivalate,desoximethasone, estradiol, fludrocortisone, fludrocortisoneacetate,dichlorisone acetate, fluorohydrocortisone, fluorometholone,fluprednisolone, paramethasone, paramethasone acetate, androsterone,fluoxymesterone, aldosterone, methandrostenolone, methylandrostenediol,methyl testosterone, norethandrolone, testosterone,testosteroneenanthate, testosterone propionate, equilenin, equilin,estradiol benzoate, estradiol dipropionate, estriol, estrone, estronebenzoate, acetoxypregnenolone, anagestone acetate, chlormadinoneacetate, flurogestone acetate, hydroxymethylprogesterone,hydroxymethylprogesterone acetate, hydroxyprogesterone,hydroxyprogesterone acetate, hydroxyprogesterone caproate, melengestrolacetate, normethisterone, pregnenolone, progesterone, ethynyl estradiol,mestranol, dimethisterone, ethisterone, ethynodiol diacetate,norethindrone, norethindrone acetate, norethisterone, fluocinoloneacetonide, flurandrenolone, flunisolide, hydrocortisone sodiumsuccinate, methylprednisolone sodium succinate, prednisolone phosphatesodium, triamcinolone acetonide, hydroxydione sodium spironolactone,oxandrolone, oxymetholone, prometholone, testosterone cypionate,testosterone phenylacetate, estradiol cypionate, and norethynodrel.

Vitamins:

Vitamins, include, for example, without limitation, cyanocobalaminneinoic acid, retinoids and derivatives thereof such as retinolpalmitate, alpha-tocopherol, naphthoquinone, cholecalciferol, folic acidand tetrahydrofolate.

Peptides and Peptide Analogs:

Peptides and peptide analogs, include, for example, without limitation,manganese super oxide dismutase, tissue plasminogen activator (t-PA),glutathione, insulin, dopamine, peptide ligands containing RGD, AGD,RGE, KGD, KGE or KQAGDV (peptides with affinity for theGPEXma receptor),opiate peptides, enkephalins, endorphins and their analogs, humanchorionicgonadotropin (HCG), corticotropin release factor (CRF),cholecystokinins and their analogs, bradykinins and their analogs andpromoters and inhibitors, elastins, vasopressins, pepsins, glucagon,substance P, integrins, captopril, enalapril, lisinopril and other ACEinhibitors, adrenocorticotropic hormone (ACTH), oxytocin, calcitonins,IgG or fragments thereof, IgA or fragments thereof, IgM or fragmentsthereof, ligands for Effector Cell Protease Receptors (all subtypes),thrombin, streptokinase, urokinase, t-PA and all active fragments oranalogs, Protein Kinase C and its binding ligands, interferons (α-IFN,β-IFN, γ-IFN), colony stimulating factors (CSF), granulocyte colonystimulating factors (GCSF), granulocyte-macrophage colony stimulatingfactors (GM-CSF), tumor necrosis factors (TNF), nerve growth factors(NGF), platelet derived growth factors, lymphotoxin, epidermal growthfactors, fibroblast growth factors, vascular endothelial cell growthfactors, erythropoietin, transforming growth factors, oncostatin M,interleukins (IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9,IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-19,IL-20, etc.), metalloprotein kinase ligands, collagenases and agonistsand antagonists.

Antibodies:

Antibodies, include, for example, without limitation, substantiallypurified antibodies or fragments thereof, including non-human antibodiesor fragments thereof. In various embodiments, the substantially purifiedantibodies or fragments thereof, can be human, non-human, chimericand/or humanized antibodies. Such non-human antibodies can be goat,mouse, sheep, horse, chicken, rabbit, or rat antibodies. Alternatively,the non-human antibodies of the invention can be chimeric and/orhumanized antibodies. Completely human antibodies are particularlydesirable for therapeutic treatment of human patients. A chimericantibody is a molecule in which different portions are derived fromdifferent animal species, such as those having a variable region derivedfrom a murine monoclonal antibody (mAb) and a human immunoglobulinconstant region (Cabilly et al., U.S. Pat. No. 4,816,567; and Boss etal., U.S. Pat. No. 4,816,397, which are incorporated herein by referencein their entirety.). In addition, the non-human antibodies could bepolyclonal antibodies or monoclonal antibodies. Any of the antibodiesused with the microspheres of the invention can be conjugated to atherapeutic moiety or to a detectable substance. Non-limiting examplesof detectable substances that can be conjugated to the antibodies of theinvention are an enzyme, a prosthetic group, a fluorescent material, aluminescent material, a bioluminescent material, and a radioactivematerial. The term “monoclonal antibody” or “monoclonal antibodycomposition,” as used herein, refers to a population of antibodymolecules that contain only one species of an antigen binding sitecapable of immunoreacting with a particular epitope. Polyclonalantibodies can be prepared as described above by immunizing a suitablesubject with a polypeptide of the invention as an immunogen. Preferredpolyclonal antibody compositions are ones that have been selected forantibodies directed against a polypeptide or polypeptides of, forexample, a receptor on the surface of a cancer cell of a tumor to betreated by the compositions of the present invention.

Anti-Mitotic Factors:

Anti-mitotic factors include, without limitation, estramustine and itsphosphorylated derivative, estramustine-phosphate, doxorubicin,amphethinile, combretastatin A4, and colchicine.

Vaccines:

Vaccines include, for example, without limitation, pneumococcus vaccine,poliomyelitis vaccine, anthrax vaccine, tuberculosis (BCG) vaccine,hepatitis A vaccine, cholera vaccine, meningococcus A, C, Y vaccines,W135 vaccine, plague vaccine, rabies (human diploid) vaccine, yellowfever vaccine, Japanese encephalitis vaccine, typhoid (phenol andheat-killed) vaccine, hepatitis B vaccine, diptheria vaccine, tetanusvaccine, pertussis vaccine, H. influenzae type b vaccine, polio vaccine,measles vaccine, mumps vaccine, rubella vaccine, varicella vaccine,streptococcus pneumoniae Ty (live mutant bacteria) vaccine, Vi (Vicapsular polysaccharide) vaccine, DT (toxoid) vaccine, Td (toxoid)vaccine, aP (inactive bacterial antigen/accelular (DtaP)) vaccine, Hib(bacterial polysaccharide-protein conjugate) vaccine, hepatitis B virus(inactive serum derived viral antigen/recombinant antigen) vaccine,influenza vaccine, rotavirus vaccine, respiratory syncytial virus (RSV)vaccine, human astrovirus vaccine, rotavirus vaccine, human influenza Aand B virus vaccine, hepatitis A virus vaccine, live attenuatedparainfluenza virus type 3 vaccine, enterovirus vaccines, retrovirusvaccines, and picomavirus vaccines.

Anti-Allergenic Agents:

Anti-allergenic agents, include, for example, without limitation,amelexanox.

Anti-Coagulation Agents:

Anti-coagulation agents, include, for example, without limitation,phenprocoumon and heparin.

Circulatory Drugs:

Circulatory drugs, include, for example, without limitation,propranolol.

Anti-Tubercular Agents

Anti-tubercular agents, include, for example, without limitation,para-aminosalicylic acid, isoniazid, capreomycin sulfatecycloserine,ethambutol hydrochloride ethionamide, pyrazinamide, rifampin, andstreptomycin sulfate.

Anti-Viral Agents:

Anti-viral agents, include, for example, without limitation, acyclovir,amantadine azidothymidine (AZT or Zidovudine), ribavirin, and vidarabinemonohydrate (adenine arabinoside,ara-A).

Anti-Anginal Agents:

Anti-anginal agents, include, for example, without limitation,diltiazem, nifedipine, verapamil, erythritol tetranitrate, isosorbidedinitrate, nitroglycerin (glyceryl trinitrate), andpentaerythritolteiranitrate.

Antibiotics:

Antibiotics, include, for example, dapsone, chloramphenicol, neomycin,cefaclor, cefadroxil, cephalexin, cephradine erythromycin, clindamycin,lincomycin, amoxicillin, ampicillin, bacampicillin, carbenicillin,dicloxacillin, cyclacillin, picloxacillin, hetacillin, methicillin,nafcillin, oxacillin, penicillin G, penicillin V, ticarcillin, rifampin,and tetracycline.

Anti-Inflammatory Agents and Analgesics:

Anti-inflammatory agents and analgesics, include, for example,diflunisal, ibuprofen, indomethacin, meclofenamate, mefenamic acid,naproxen, oxyphenbutazone, phenylbutazone, piroxicam, sulindac,tolmetin, aspirin and salicylates.

Anti-Protozoan Agents:

Anti-prozoan agents, include, for example, without limitation,chloroquine, metronidazole, hydroxychloroquine, quinine, andmeglumineantimonate.

Anti-Rheumatic Agents:

Anti-rheumatic agents, include, for example, without limitation,penicillamine.

Narcotics:

Narcotics, include, for example, without limitation, paregoric andopiates, such as codeine, heroin, methadone, morphine and opium.

Cardiac Glycoside Agents:

Cardiac glycoside agents, include, for example, without limitation,deslanoside, digitoxin, digoxin, digitalin and digitalis.

Neuromuscular Blocking Agents:

Neuromuscular blocking agents, include, for example, without limitation,atracurium mesylate, gallamine triethiodide, hexafluorenium bromide,metocurine iodide, pancuronium bromide, succinylcholinechloride(suxamethonium chloride), tubocurarine chloride, and vecuroniumbromide.

Sedatives (Hypnotics):

Sedatives, include, for example, without limitation, amobarbital,amobarbital sodium, aprobarbital, butabarbital sodium, chloral hydrate,ethchlorvynol, ethinamate, flurazepam hydrochloride, glutethimide,methotrimeprazine hydrochloride, methyprylon, midazolam hydrochlorideparaldehyde, pentobarbital, pentobarbital sodium, phenobarbital sodium,secobarbital sodium, talbutal, temazepam, and triazolam.

Local Anesthetic Agents:

Local anesthetic agents, include, for example, without limitation,bupivacaine hydrochloride, chloroprocaine hydrochloride, etidocainehydrochloride, lidocaine hydrochloride, mepivacaine hydrochloride,procaine hydrochloride, and tetracaine hydrochloride.

General Anesthetic Agents:

General anesthetic agents, include, for example, without limitation,droperidol, etomidate, fentanyl citrate with droperidol, ketaminehydrochloride, methohexital sodium, and thiopental sodium.

Radioactive Particles or Ions:

Radioactive particles or ions, include, for example, without limitation,strontium, rhenium, yttrium, technetium, and cobalt.

Cell-Adhesion Promoters:

In some embodiments, the microspheres can comprise a cell adhesionpromoter. Various types of cell adhesion promoters well known in the artcan be used in the present invention. In particular, cell adhesionpromoters can be selected from collagen, gelatin, glucosaminoglycans,fibronectins, lectins, polycations (such polylysine, chitosan and thelike), or any other natural or synthetic biological cell adhesion agent.Preferably, the cell adhesion promoter is present in the microsphere, orother solid substrate, in an amount between about 0.1 to 1 g per ml ofsettled microspheres.

The targeting aspects of the invention further enable lowered dosages tobe applied for therapy, since the effective concentration at thetherapeutic site remains undiluted in the body. The amount of the drugor agent of the present invention to be administered to a patientdepends, for example, on the particular drug or agent that is used, themethod in which the drug/agent is being administered, and the age, sex,weight and physical condition of the patient. Generally, treatment isinitiated with small dosages, which can then be increased by smallincrements, until the desired effect under the circumstances isachieved. Additionally, one skilled in the art can rely on referencematerials, such as the Physician's Desk Reference, published by MedicalEconomics Company at Montvale, N.J., to determine the appropriate amountof a particular drugs/agents, and hence such a dose or a lower or higherdose can be administered to a patient using the methods of the presentinvention. In accordance with the present invention, the prodrug isdelivered to the patient (e.g., in a region of the patient) for thepurposes, for example, of treating a condition (i.e., a disease state,malady, disorder, etc.) in the patient. The prodrugs can be used asabove or can be incorporated into other embodiments, such as emulsions.

Diseases contemplated for treatment with the compositions and methods ofthe present invention include, for example, without limitation, tumorsassociated with the liver, kidney, acute lymphoblastic leukemia, acutemyeloid leukemia, Ewing's sarcoma, gestational trophoblastic carcinoma,Hodgkin's disease, non-Hodgkin's lymphoma, Burkitt's lymphoma diffuselarge cell lymphoma, follicular mixed lymphoma, lymphoblastic lymphoma,rhabdomyosarcoma, testicular carcinoma, wilms's tumor, anal carcinoma,bladder carcinoma, breast carcinoma, chronic lymphocytic leukemia,chronic myelogenous leukemia, hairy cell leukemia, head and neckcarcinoma, meningioma, neuro fibrosoma, angio fibrosoma, lung (smallcell) carcinoma, multiple myeloma, Non-Hodgkin's lymphoma, follicularlymphoma, ovarian carcinoma, brain tumors (astrocytoma), cervicalcarcinoma, colorectal carcinoma, hepatocellular carcinoma, human largehepatocellular carcinoma, Kaposi's sarcoma, lung (non-small-cell)carcinoma, melanoma, pancreatic carcinoma, prostate carcinoma, softtissue sarcoma, breast carcinoma, colorectal carcinoma (stage II), bonetumors, osteogenic sarcoma, ovarian carcinoma, uterine fibroids,testicular carcinoma, or combinations thereof.

Embolization therapy and/or drug delivery of the present invention maybe utilized in at least three principal ways to assist in the managementor treatment of neoplasms: (1) definitive treatment of tumors (usuallybenign); (2) for preoperative embolization; and (3) for palliativeembolization. Briefly, benign tumors may sometimes be successfullytreated by embolization therapy alone. Examples of such tumors includesimple tumors of vascular origin (e.g., haemangiomas), endocrine tumorssuch as parathyroid adenomas, and benign bone tumors.

For other tumors, (e.g., renal adenocarcinoma), preoperativeembolization and/or drug delivery may be employed hours or days beforesurgical resection in order to reduce operative blood loss, shorten theduration of the operation, and reduce the risk of dissemination ofviable malignant cells by surgical manipulation of the tumor. Manytumors may be successfully embolized and/or drugs can be deliveredpreoperatively, including for example nasopharyngeal tumors, glomusjugular tumors, meningiomas, chemodectomas, and vagal neuromas.

It should be evident that a wide variety of tumors may be treated, suchas by embolization and/or by drug-delivery, using the methods andcompositions of the present invention. Briefly, tumors are typicallydivided into two classes: benign and malignant. In a benign tumor thecells retain their differentiated features and do not divide in acompletely uncontrolled manner. In addition, the tumor is localized andnon-metastatic. In a malignant tumor, the cells become undifferentiated,do not respond to the body's growth and hormonal signals, and multiplyin an uncontrolled manner; the tumor is invasive and capable ofspreading to distant sites (metastasizing).

Within one aspect of the present invention, metastases (secondarytumors) of the liver may be treated utilizing the compositions andmethods of the present invention by embolization therapy and/or drugdelivery. Briefly, a catheter can be inserted via the femoral orbrachial artery and advanced into the hepatic artery by steering itthrough the arterial system under fluoroscopic guidance. The cathetercan be advanced into the hepatic arterial tree as far as necessary toallow complete blockage of the blood vessels supplying the tumor(s),while sparing as many of the arterial branches supplying normalstructures as possible. In certain embodiments, this will be a segmentalbranch of the hepatic artery, but it could be that the entire hepaticartery distal to the origin of the gastroduodenal artery, or evenmultiple separate arteries, will need to be blocked depending on theextent of tumor and its individual blood supply. Once the desiredcatheter position is achieved, the artery can be embolized by injectinganti-angiogenic therapeutic compositions through the arterial catheteruntil flow in the artery to be blocked ceases, preferably even afterobservation for 5 minutes. Occlusion of the artery may be confirmed byinjecting radiopaque contrast through the catheter and demonstrating byfluoroscopy or X-ray film that the vessel which previously filled withcontrast no longer does so. The same procedure may be repeated with eachfeeding artery to be occluded.

Within another aspect of the present-invention, active therapeuticembolization therapy can be used during surgery to remove a tumor orvascular mass or cancerous organ. Additionally, another aspect of thepresent invention concerns the use of active therapeutic embolizationtherapy to prevent or ameliorate metastasis.

As noted above, both benign and malignant tumors can be targets of thecompositions and methods of the present invention. Representativeexamples of benign hepatic tumors include hepatocellular adenoma,cavernous haemangioma, and focal nodular hyperplasia. Other benigntumors, which are more rare and often do not have clinicalmanifestations, may also be treated. These include bile duct adenomas,bile duct cystadenomas, fibromas, lipomas, leiomyomas, mesotheliomas,teratomas, myxomas, and nodular regenerative hyperplasia.

Malignant hepatic tumors are generally subdivided into two categories:primary and secondary. Primary tumors arise directly from the tissue inwhich they are found. Thus, a primary liver tumor is derived originallyfrom the cells which make up the liver tissue (such as hepatocytes andbiliary cells). Representative examples of primary hepatic malignancieswhich may be treated by arterial embolization includehepatocellularcarcinoma, cholangiocarcinoma, angiosarcoma,cystadenocarcinoma, squamous cell carcinoma, and hepatoblastoma.

A secondary tumor, or metastasis, is a tumor which originated elsewherein the body but has subsequently spread to a distant organ. The commonroutes for metastasis are direct growth into adjacent structures, spreadthrough the vascular or lymphatic systems, and tracking along tissueplanes and body spaces (peritoneal fluid, cerebrospinal fluid, etc.).Secondary hepatic tumors are one of the most common causes of death inthe cancer patient and are by far and away the most common form of livertumor. Although virtually any malignancy can metastasize to the liver,tumors which are most likely to spread to the liver include: cancer ofthe stomach, colon, and pancreas; melanoma; tumors of the lung,oropharynx, and bladder; Hodgkin's and non-Hodgkin's lymphoma; tumors ofthe breast, ovary, and prostate. Each one of the above-named primarytumors has numerous different tumor types which may be treated byarterial embolization (for example, without limitation, there arereportedly over 32 different types of ovarian cancer).

Methods of Administration

The diseases or disorders above can be treated or prevented byadministering to the mammal in need thereof a therapeutically effectiveamount of the microspheres or a pharmaceutical composition according tothe invention. The microspheres can be administered in their completelyswollen state or also in a partially swollen state.

Administration is typically carried out by injection. In certainembodiments, the microspheres are administered by a catheter. In otherembodiments, the microspheres are injected us a needle attached to asyringe. In some embodiments, administration is into a blood vessel. Inother embodiments, administration is directly to the site of action, forexample into a tumor mass, or into a cell, organ or tissue requiringsuch treatment. The microspheres according to the invention can beadministered already loaded with a drug. In other embodiments, themicrospheres are administered in combination with a drug solution,wherein the drug solution is administered prior, simultaneously or afterthe administration of the microspheres.

When administered, the microspheres or the pharmaceutical compositionare suitable for injection. In specific embodiments, the microspheres orcompositions comprising the microspheres are sterile.

Kits

The invention further relates to pharmaceutical packs and kitscomprising one or more containers filled with one or more of theingredients of the aforementioned compositions of the invention. Thekits can comprise microspheres, a contrast agent, and solutioncomprising one or more drugs, wherein one, two, three or more of thecomponents can be in one, two, three or more vials. Associated with suchcontainer(s) can be a notice in the form prescribed by a governmentalagency regulating the manufacture, use or sale of pharmaceuticals orbiological products, reflecting approval by the agency of themanufacture, use or sale of the product for patient (e.g., human orother mammal) administration. The reagents of any of the assays ormethods described herein can also be included as components of a kit.

In one kit format, the microspheres of the present invention are presentin a liquid, physiologically compatible solution in one vial. In anotherkit format, the microspheres of the present invention can be provided indry form in one vial and the drug solution and contrast agent can beprovided in a second and/or optionally a third vial. In certainembodiments, the microsphere comprising the contrast agent are presentin one vial, and the drug is present in solution in another vial. Inthis form, the contents of the two vials can be mixed together prior toor concurrently with administration. In other embodiments, themicrospheres comprising the contrast agent and the drug are provided indry form in one vial. The powder can then be suspended in a suitableliquid prior to administration or a second vial is provided, whichcontains the injectable solution and the contents of both vials arecombined prior to administration or concurrently with administration.

Finally, in another kit format the microspheres of the present inventionare present in one vial and a second vial contains a pharmaceuticallyacceptable solution comprising the contrast agent. The microspheres inthe first vial can be pre-loaded with a drug, or the drug solution canoptionally be present in a third vial. The microspheres can then bemixed together with the drug solution and/or contrast agent, forexample, prior to or concurrently with administration.

The following examples are offered by way of illustration, and not byway of limitation.

EXAMPLE 1 Preparation of Microspheres

One-half of a gram of benzoyl peroxide as a polymerization initiator isadded to 60 g of vinyl acetate and 40 g of methyl acrylate. This isdispersed in 300 ml of water containing 3 g of partially saponifiedpolyvinylalcohol as a dispersion stabilizer and 10 g of NaCl. Thesuspension polymerization is carried at 65° C. for 6 hours. Afterremoving the solvent, the polymer is dried for 24 hours in a freezedryer. Twenty grams of the dried powder is suspended in a saponificationfluid containing 200 g of methanol and 10 g of water. Then 40 ml of 10 NNaOH solution was added drop wise by maintaining the reaction at 10° C.,and then the reaction was carried out at 30° C. for 24 hours. After thesaponification reaction is completed, the reaction product is washedwith methanol, after which 15.8 g of spherical dry saponified productwith a particle diameter of about 50 μm to about 240 μm is obtainedafter drying. The product is then sieved and calibrated into, e.g.,about 50 μm increments, to get several size ranges, e.g., about 50μm-100 μm, about 100 μm-150 μm, about 150 μm-210 μm. The sieved productscan then be lyophilized.

EXAMPLE 2 Preparation of Microspheres with Non-Ionic Contrast Agent

One hundred milligrams of dry microspheres obtained as described abovein Example 1 are added to 10 ml of a iodixanol solution (e.g.,Visipaque™, Nycomed, 320 mg iodine/ml), and about 1 ml of supernatantremains.

The (wet) microspheres can be sterilized, for example, by irradiationand are then ready for use. Alternatively, the microspheres can belyophilized and stored.

EXAMPLE 3 Preparation of Drug-Loaded Microspheres with Non-IonicContrast Agent

To the 100 mg of microspheres obtained in Example 1 are added 5 ml of adoxorubicin solution (e.g., Adriamycin™, 2 mg/ml), and the solution iscompletely absorbed. Then 5 ml of a iodixanol solution (e.g.,Visipaque™, Amersham, 320 mg/ml iodine) is added. About 1 ml of clearsupernatant remains.

The microspheres can optionally be sterilized and used for injectioninto a patient.

EXAMPLE 4 Preparation of Drug-Loaded Microspheres with Contrast Agent

To compare the swellability, compressibility and loading capacity ofdrug-loaded PVA-containing microspheres with non-ionic versus ioniccontrast media, the following experiment can be performed. While thisexperiment uses an ionic contrast agent, a parallel experiment can alsobe run using a non-ionic contrast agent (see, e.g., Example 5).

One hundred micrograms of the microspheres obtained in Example 1 areadded to 5 ml of a doxorubicin solution (e.g., Adriamycin™, 2 mg/ml) andthe solution is completely absorbed. Then 5 ml of a ioxaglate (e.g.,Hexabrix®), Mallinckrodt, 320 mg/ml of iodine) solution is added. Thesupernatant shows the red color of the doxorubicin solution, showingthat doxorubicin leaked from the microspheres after addition of ioniccontrast agent.

A comparison of the results of drug-loaded microspheres in the presenceof ionic versus non-ionic contrast agent will show that PVA-containingmicrospheres comprising a non-ionic contrast agent have increasedloading capacity as compared to those comprising ionic contrast agents.For example, in some instances, microspheres plus human serum (e.g., 5ml) and ionic contrast agent (50/50) results in a swelling rate of about3.9, whereas the same mixture with a non-ionic contrast agent results ina swelling rate of about 4.8 (123%).

EXAMPLE 5 Comparative Drug Release

A typical release experiment can be performed as follows:

A solution of doxorubicin hydrochloride (50 mg in 5 ml of saline fromHaorui Pharma Chem, Inc.) was added to 100 mg of dry microspheresprepared as described in Example 1. Microspheres of a size range from 50μm to 100 μm were used. After 25 minutes, 5 ml of contrast agent wasadded. Two different contrast agents were used in separate experiments:Hexabrix 320® (ionic contrast agent) and Visipaque 320% (non-ioniccontrast agent). The microsphere suspension was then transferred into a10 ml dialysis membrane (Spectrapor®, MW 100,000) without removal ofsupernatant and the dialysis membrane was sealed.

The dialysis membrane was placed in a graded cylinder filled with asolution of 450 ml saline (0.9% wt. NaCl) and 50 ml methanol. The stirbar was added to the cylinder, and the stirring speed was set to low.Samples of 150 μl were taken at different time intervals and examinedfor the concentration of doxorubicin. The concentration of doxorubicinin the samples was measured by HPLC (Waters, Interchrom columnUptisphere, UV detection at 480 nm).

The experiments showed that after 72 hours about 0.8% wt of theoriginally present doxorubicin had been released from the microspheresloaded with the non-ionic contrast agent, while 3.0% doxorubicin wasreleased from the microspheres containing the ionic contrast agent.

The embodiments of the present invention described above are intended tobe merely exemplary, and those skilled in the art will recognize, or beable to ascertain using no more than routine experimentation, numerousequivalents to the specific procedures described herein. All suchequivalents are considered to be within the scope of the presentinvention and are covered by the following claims. Furthermore, as usedin this specification and claims, the singular forms “a,” “an” and “the”include plural forms unless the content clearly dictates otherwise.Thus, for example, reference to “a drug” includes a mixture of two ormore such drugs, reference to “a microsphere” includes mixtures of twoor more such microspheres, and the like. Additionally, ordinarilyskilled artisans will recognize that operational sequences must be setforth in some specific order for the purpose of explanation andclaiming, but the present invention contemplates various changes beyondsuch specific order.

The contents of all references described herein are hereby incorporatedby reference.

Other embodiments are within the following claims.

1. A substantially spherical microsphere suitable for activeembolization and/or drug delivery comprising: (a) a non-ionic contrastagent, (b) at least one drug, and (c) a biocompatible polymeric materialcomprising a polyvinylalcohol polymer or copolymer, an acrylic acidpolymer or copolymer, an acrylamide polymer or copolymer, an acrylamidepolymer or copolymer, or an acrylic acid ester polymer or copolymer,wherein the microsphere is swellable in a pharmaceutically acceptablesolution and has a diameter of from about 10 μm to about 2000 μm beforeswelling.
 2. The microsphere of claim 1, wherein the polymeric materialis superabsorbent.
 3. The microsphere of claim 1, wherein the polymericmaterial further comprises a polyacrylate, polyacetal, polyamide,polycarbonate, polyester, polyimide, polyolefin, polyurethane,polystyrene, polysaccharide or a mixture thereof.
 4. The microsphere ofclaim 1, wherein the polymeric material comprises apolyvinylalcohol-polyacrylate copolymer.
 5. The microsphere of claim 4,wherein the polyacrylate is selected from the group consisting of sodiumacrylate, potassium acrylate, ammonium acrylate, and mixtures thereof.6. The microsphere of claim 1, wherein the biocompatible polymericmaterial is a polyvinylalcohol and sodium acrylate copolymer.
 7. Themicrosphere of claim 1, wherein the polyvinylalcohol is notcross-linked.
 8. The microsphere of claim 1, wherein thepolyvinylalcohol is cross-linked.
 9. The microsphere of claim 1, whereinthe drug is selected from the group consisting of anti-neoplastic drugs,anti-angiogenesis drugs, anti-fungal drugs, anti-viral drugs,anti-inflammatory drugs, anti-bacterial drugs, anti-histamine drugs,pain-relieving drugs, and mixtures thereof.
 10. The microsphere of claim1, wherein the drug is an anti-neoplastic drug selected from the groupconsisting of actinomycin D, aldesleukin, alemtuzumab, alitretinoin,allopurinol, altretamine, amifostine, aminoglutehimide, amphotercin B,amsacrine, anastrozole, ansamitocin, arabinosyl adenine, arsenictrioxide, asparaginase, aspariginase Erwinia, BCG Live, benzamide,bevacizumab, bexarotene, bleomycin, 3-bromopyruvate, busulfan,calusterone, capecitabine, carboplatin, carzelesin, carmustine,celecoxib, chlorambucil, cisplatin, cladribine, cyclophosphamide,cytarabine, cytosine arabinoside, dacarbazine, dactinomycin, Darbepoetinalfa, daunorubicin, daunomycin, denileukin diftitox, dexrazoxane,dexamethosone, docetaxel, doxorubicin, dromostanolone, epirubicin,Epoetin alfa, estramustine, estramustine, etoposide, VP-16, exemestane,filgrastim, floxuridine, fludarabine, fluorouracil (5-FU), flutamide,fulvestrant, demcitabine, gemcitabine, gemtuzumab, goserelin acetate,hydroxyurea, ibritumomab, idarubicin, ifosfamide, imatinib, interferon(e.g., interferon α-2a, interferon α-2b), imiotecan, letrozole,leucovorin, leuprolide, lomustine, meciorthamine, megestrol, melphalan,mercaptopurine, mercaptopolylysine, mesna, mesylate, methotrexate,methoxsalen, mithramycin, mitomycin, mitotane, mitoxantrone, nandrolonephenpropionate, nolvadex, oprelvekin, oxaliplatin, paclitaxel,pamidronate sodium, pegademase, pegaspargase, pegfilgrastim,pentostatin, pipobroman, plicamycin, porfimer sodium, procarbazine,quinacrine, raltitrexed, rasburicase, riboside, rituximab, sargramostim,spiroplatin, streptozocin, tamoxifen, tegafur-uracil, temozolomide,teniposide, testolactone, tioguanine, thiotepa, tissue plasminogenactivator, topotecan, toremifene, tositumomab, trastuzumab, treosulfan,tretinoin, trilostane valrubicin, vinblastine, vincristine, vindesine,vinorelbine, zoledronate, salts thereof, or mixtures thereof.
 11. Themicrosphere of claim 1, wherein the drug is cisplatin, mitomycin,paclitaxel, tamoxifen, doxorubicin, tamoxifen, or mixtures thereof. 12.The microsphere of claim 9, wherein the drug is a pain-relieving drugselected from the group consisting of ibuprofen, ketoprofen,dexketoprofen, phenyltoloxamine, chlorpheniramine, hurbiprofen, vioxx,celibrex, bexxstan, narbumetone, asperine, codeine, codeine phosphate,acetaminophen, hurbiprofen, paracetamol, xylocalne, salts andcombinations thereof.
 13. The microsphere of claim 1, wherein thenon-ionic contrast agent contains iodine.
 14. The microsphere of claim1, wherein the contrast agent is metrizamide, iodixanol, iohexol,ioversol, iopromide, iobitridol, iomeprol, iopentol, ioxilan, iotrolan,gadodiamide, gadoteridol, or mixtures thereof.
 15. The microsphere ofclaim 1, wherein the microsphere is about 10% to about 90% saturatedwith non-ionic contrast media and about 90% to about 10% saturated withthe at least one drug, wherein the percent indicates the percent maximumsaturation of the microsphere.
 16. The microsphere of claim 1, whereinthe diameter of the microsphere before swelling is from about 40 μm toabout 1000 μm, from about 40 μm to about 400 μm, from about 50 μm toabout 300 μm, from about 50 μm to about 200 μm, from about 70 μm toabout 120 mm, from about 10 μm to about 400 μm, from about 10 μm toabout 200 μm, from about 10 μm to about 120 μm, from about 10 μm toabout 50 μm, from about 50 μm to about 100 μm, from about 53 μm to about106 μm, from about 100 μm to about 150 μm, from about 106 μm to about150 μm, from about 150 μm to about 200 μm, from about 150 μm to about212 μm, from about 200 μm to about 250 μm, about 212 μm to about 250 μm,from about 250 μm to about 300 μm, from about 300 μm to about 350 μm,from about 350 μm to about 400 μm, from about 400 μm to about 450 μm, orfrom about 450 μm to about 500 μm.
 17. The microsphere of claim 1,wherein the diameter of the microsphere after swelling is from about 10μm to about 2000 μm, from about 10 μm to about 1500 μm, from about 10 μmto about 1000 μm, from about 10 μm to about 500 μm, from about 10 μm toabout 250 μm, from about 10 μm to about 150 μm, from about 750 μm toabout 880 μm, or from about 1050 μm to about 1230 μm.
 18. Themicrosphere of claim 1, wherein the microsphere swells prior toinjection into a patient.
 19. The microsphere of claim 1, wherein themicrosphere swells after injection into a patient.
 20. An injectablecomposition comprising the microsphere of claim 1 and a biocompatiblecarrier.
 21. A method for active embolization in a mammal, comprisingadministering to the mammal in need of treatment thereof a substantiallyspherical microsphere comprising: (a) a non-ionic contrast agent, (b) atleast one drug, and (c) a biocompatible polymeric material comprisingpolyvinylalcohol, an acrylic acid polymer or copolymer, an acrylamidepolymer or copolymer, an acrylamide polymer or copolymer, or an acrylicacid ester polymer or copolymer, wherein the microsphere is swellable ina pharmaceutically acceptable solution and has a diameter of from about10 μm to about 2000 μm before swelling.
 22. A method for drug deliveryin a mammal, comprising administering to the mammal in need of treatmentthereof a substantially spherical microsphere comprising: (a) anon-ionic contrast agent, (b) at least one drug, and (c) a biocompatiblepolymeric material comprising polyvinylalcohol, an acrylic acid polymeror copolymer, an acrylamide polymer or copolymer, an acrylamide polymeror copolymer, or an acrylic acid ester polymer or copolymer, wherein themicrosphere is swellable in a pharmaceutically acceptable solution andhas a diameter of from about 10 μm to about 2000 μm before swelling.